It does sound like the change they're implementing is just a restructuring of the data into a smaller object structure, not a new data interchange syntax.

A recent arrival in the JSON arena is JSON.hpack (http://wiki.github.com/WebReflection/json.hpack), which is a useful method to optimize compression of repetitive data structures, such as database query results. We'll be keeping an eye on the evolution of this proposal and potentially adding support/hooks for creating or parsing hpacked JSON.